The present invention relates to a two dimensional color pick-up apparatus comprising a solid state image sensor.
Such a color pick-up apparatus is used to pick-up a transparent or opaque color document to generate red (R), green (G) and blue (B) color signals or an NTSC color television signal. In case of generating the NTSC color television signal, use has been made of a color television camera or a flying spot scanner (FSS). In CCTV (closed circuit television) and various kinds of image processing apparatuses, the three primary color signals are sometimes used. In accordance with recent progress in the color image processing art, it has been earnestly desired to develop a color pick-up apparatus which can generate R, G and B color signals having high resolution and S/N.
Heretofore, in order to derive the R, G and B color signals, the illuminated color document is picked up by a color television camera. However, the number of scanning lines per frame of the color television camera is limited to 525 or 625 lines and thus fine patterns, figures and characters could not be picked up accurately. Further, it is very difficult to remove so-called shading due to an optical system including an objective lens and an illumination system. In another method for deriving the R, G and B color signals, a standard FSS apparatus is used to pick up the color document. This apparatus has the drawbacks that the size of the document is limited and the whole apparatus is liable to be large due to a large FSS tube. It is possible to construct the FSS apparatus so as to pick up documents having an arbitrary size. However, since flare due to multiple reflection within a screen plate of the FSS tube could not be eliminated completely, its resolution might be limited. Moreover, the shading due to the optical system and illumination system could not be deleted and further the raster distortion could be hardly eliminated.
Ther has been further proposed an electronic camera comprising a CCD two dimensional image sensor and a magnetic disc memory. However, the number of picture elements of the CCD two dimensional image sensor is limited only to a small value and thus, the resolution of the reproduced image is low.